The Daguerreotype: Contemporary work by Jonathan Danforth

Iodine is critical to photography.  Like the other halogens, Iodine forms a light-reactive salt when exposed to silver called Silver Iodide.  Expose the Silver Iodide to light and PRESTO! it turns black.  Cool, huh?  This reaction is so critical to photography and to daguerreotypes in particular that I made the molecule my logo.

One of the thing’s that’s so awesome about Iodine is that it is one of a fairly small group of subliming elements.  Sublimation is the process by which a compound transitions from solid to gas without first taking a little time out to be a liquid.  They just want to jump the gun and get right to work.

In daguerreotypy we rely on the gaseous Iodine to float up and react with the polished silver on our plates to form that oh-so-delicious useful silver salt.  If your daguerreotype manufacturing building (shed?) is poorly heated, like mine, then the winter makes it really annoying to make daguerreotypes.  In the Summer when it hovers around 85 in my studio I might sensitize a plate over Iodine for 30 seconds.  The same plate in the Winter requires five or more minutes.

Crystal Iodine is, in the USA, a List 1 restricted compound.  The “controlled substance” they mention is methamphetamine (that should generate some unwanted Google hits).  Meth, by the way, is something you DON’T want to use OR make.

The term List I chemical means a chemical specifically designated by the Administrator in Sec. 1310.02(a) of this chapter that, in addition to legitimate uses, is used in manufacturing a controlled substance in violation of the Act and is important to the manufacture of a controlled substance.

(source)

What that means is that you have to fill out a big scary form and make the Drug Enforcement Agency aware of your intentions for using the stuff in order to buy it.  If you’d rather not get on a DEA list or if you live in a more sane country, Here’s how to extract your own Iodine from common household items.

Don’t get too comfortable yet.  Iodine is dangerous stuff.  Here’s the MSDS safety sheet.  In addition to corroding the hell out of almost every metal it comes in contact with it will cause all number of problems with your interior bits.  Use ventilation!  It’s also generally a good idea to wear a mask that has received a NIOSH rating to handle Chlorine gas.

If you’re making something to hold Iodine then I can suggest wood.  Metals are almost universally hopeless but there are exceptions.  Titanium would be a good choice for hardware in a sensitizing box.